[IMP] Report: handling of ir.values similar to the server actions one

When creating an ir.actions.report.xml record from the backend, ir.values allowing to display a report in the contextual more menu are not created. Added a button to force the creation.
Could you double-check that we indeed need to do this as super-user? If yes, then we need to check that the user belongs to the admin group (via `user.has_group()`) or at least has the right to modify `ir.actions.act_report_xml` (via `self.check_access()`). The same should be done for `ir.actions.server`, presumably.
For `create_action()` this is indirectly verified by the second `write()` call in `ir_actions_report_xml`, done as `uid`.